21261661150353 has 16 divisors (see below), whose sum is σ = 32136383926080. Its totient is φ = 12395462370624.

The previous prime is 21261661150349. The next prime is 21261661150393. The reversal of 21261661150353 is 35305116616212.

It is a happy number.

It is not a de Polignac number, because 21261661150353 - 2² = 21261661150349 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21261661150393) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14346599226 + ... + 14346600707.

It is an arithmetic number, because the mean of its divisors is an integer number (2008523995380).

Almost surely, 2^{21261661150353} is an apocalyptic number.

It is an amenable number.

21261661150353 is a deficient number, since it is larger than the sum of its proper divisors (10874722775727).

21261661150353 is a wasteful number, since it uses less digits than its factorization.

21261661150353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28693199968.

The product of its (nonzero) digits is 194400, while the sum is 42.

Adding to 21261661150353 its reverse (35305116616212), we get a palindrome (56566777766565).

The spelling of 21261661150353 in words is "twenty-one trillion, two hundred sixty-one billion, six hundred sixty-one million, one hundred fifty thousand, three hundred fifty-three".